Inhomogeneous Behavior of Concrete Columns under Critical Loads of Design Codes

After earthquakes it becomes very visible what types of building construction have withstood the forces of the earthquake and which did not perform adequately. Analyzing the nearly collapsed and broken structures gives a good insight in the possible architectural and engineering design mistakes, faults in the detailing and the mismanagement of the construction by the building contractors. Stability calculations are critical in structural design can cause significant damage to structural column members. In discussing the stability of structural systems, the goal is the investigation of the equilibrium condition from the point view of stability and instability and determines the conditions which make the system unstable. The stability is considered for relatively thin columns with small cross section area like steel sections and is rarely discussed in usual problems of structural engineering related to reinforced concrete sections and is propounded in special structures. Concrete is a non-homogeneous and anisotropic material. Modeling the mechanical behavior of Reinforced Concrete (RC) is still one of the most difficult challenges in the field of structural engineering. There are some factors which cause the mechanical factors of concrete in right dimension are not uniform and isotropic in high columns. These factors effect o